Aqueous textile finishing composition containing methylol higher fatty acid monoamides



Patented Apr. 27, 1954 UNITED STATES PATENT OFFICE AQUEOUS TEXTILEFENISHHNG COMPOSI- TION CONTAINING METHYLOL HIGHER FATTY ACID MONOAMIDESNoDrawing. Application January 9, 1952, Serial No. 265,714

6 Claims.

This invention relates 'to textile finishing compositions andparticularly to compositions which impart water-repellency anddimensional stability to fabrics which are treated therewith.

There has been a demand in the textile trade recently for cellulosicfabrics which are waterrepellent, crease-resistant, dimensionally stableand which have a firm hand. Water-'repellency may be obtained by the useof a number of known hydrophobic materials, one of which is methylolstearamide. A variety of resins may be applied in order to secure thedesired degree of dimensional stability. The various water-repellentagents are insoluble in water and must be applied either fromnon-aqueous solutions or from aqueous dispersions. The use of aqueousmedia is preferable from the standpoint of economy and convenience, butis often not possible because of the difliculty in preparing stableaqueous dispersions of the water-repellent agents.

It is an object of this invention to provide new compositions in theform of stable aqueous dispersions which are inexpensive and easy toapply to textile fabrics, and which produce durable waterrepellency anddimensional stability in the fabric. A further object is to provide aprocessby which such stable aqueous dispersions are prepared. Furtherobjects will appear from the detailed description which follows.

The compositions of this invention consist of aqueous dispersions ofmethylol fatty acid amides, polyvinyl alcohol and preferably awater-soluble heat-setting amide-formaldehyde resin. According to theprocess of this invention, these compositions are prepared by: 1)formingadis- .persion of methylol fatty acid amides byheating togetherat 60 to 100 0. under vigorous agitation (a) a fattyacid amide mixturewhich melts between 90 and 100 C. and in which the total content ofstearamide and palmitamide exceeds 80% :by weight, (b) water and (c) amolecular excess of formaldehyde, during a portion of which heating'stepat least the fatty acid amides and water are agitated together at atemperature between the melting point of the amide mixture and 100 C. toemulsifythe amides, and during asubsequent portion of which thedispersed fatty acid amides, formaldehyde and water are agitated at pH7.5 to 9 and at '75 to 100 C.; (2) filtering off the methylol fatty acidamides and washing out the excess formaldehyde from the filter cake; (3)mixing the filter cake with from l'to'30% polyvinyl alcohol in aqueoussolution and with from 2 to 5% of a water-soluble long-chain alcoholsulfate containing from 12 to 1.8 carbonatoms,

2 the percentages .in each case being based on the dry weight ofmethylol fatty acid amides in the filter cake; and (4c) mixing theresulting composition with from 1 to 15 parts by weight of awater-soluble heat-setting amide-formaldehyde resin per part of methylolfatty acid amides.

The fatty acid amide mixture which is employed as a starting material ispreferably the mixture which is sold as technical stearamide. Thisproduct contains small amounts .of free stearic acid and ofstearonitrile, up to about 10%, from 50 to stearamide and the balancepalmitamide. Amide mixtures containing large amounts of the amides of.acids having shorter chains do not provide a suflicient amount ofwater-repellency to be useful in .this connection. Such materials maybepresent so long as more than 80% of the amide mixture consists ofstearamide, palmitamide or a mixture thereof. In order to emulsify thefatty acid amide properly with water, it is necessary that the meltingpoint of the amide mixture 'be less than C. in water. Although purestearamide is reported .to melt at 109 C. andpure palmitamide at 106-107C.', the technical grade stearamide melts at about 93-98 C. in water.

A molecular excess of formaldehyde must be employed in order to obtainsubstantially complete reaction of the fatty acid amide. Someformaldehyde is lost by volatilizationand .some is decomposed by thedisproportionation which takes place in alkaline media to give methanoland a formate. It is ordinarily suitable to use a 25 to 40% excess offormaldehyde over the theoretical requirement. A .muchlarger excess doesno harm to the product but produces no corresponding advantage.

The amount of water present during formation of the methylol fatty acidamide dispersion is not critical so long as enough is added -.to give astirrable slurry. A convenient amount. is from '3'to 5Aparts of waterperpartof fatty acid amide.

The aqueous dispersion .of .methylollfatty acid amide is prepared byheating togetherat 60 .to

100 C. under vigorous agitation the .fatty .acid

amide mixture, the formaldehyde and the .water.

In an wearlyportion of this step, the fattyacid amide mixture and waterare heated together .at a temperature above the 'melting .point of theamide mixture and below the boiling point of water, in order to emulsifythe amides. Formaldehyde may be presentduringthis emulsification.

There is nooneed to control the .pI-Iat this :point.

.After the fatty acid amide mixture is thoroughly dispersed, the mixtureis heated with formaldehyde at a pH of 7.5 to 9, which is convenientlyobtained by the addition of caustic soda. The mixture is heated undervigorous agitation until reaction appears to be complete and a smoothhomogeneous dispersion is obtained. Alkalinities above pH 9 are operablebut the loss of formaldehyde through disproportionation becomessubstantial and economically undesirable. At least the latter part ofthis step is carried out at 75 to 100 C.

Considerable variation in the time of heating and the temperatureschedule is permissible so long as the over-all heating period includesthe emulsification period at a temperature between the melting point ofthe amide mixture and 100 and the subsequent reaction period underalkaline conditions at 75 to 100 C. Thus in one convenient and preferredembodiment 'of the process, the amide and water are heated together atabout 93 to 100 C. until the amide mixture is thoroughly emulsified, thetemperature is then allowed to drop to about 65, formaldehyde is added,caustic soda solution is added until the pl-l is in the desired range,and the mixture is agitated at this temperature to effect a substantialdegree of reaction. The temperature is then increased to about 80 andthe mixture is agitated at this temperature until reaction appears to becomplete. By adding the formaldehyde at the lower temperature,evaporation losses are reduced. On the other hand, the highertemperatures may be employed throughout and it is not necessary that theemulsification and the subsequent reaction with formaldehyde be carriedout as separate steps. Thus a suitable dispersion is obtained by mixingthe amide, water and formaldehyde together, adjusting the pH to therequired range and heating at a temperature between the melting point ofthe amide and 100, such as at about 95, until reaction is complete.

Vigorous agitation of the mixture is essential during the formation ofthe dispersion in order that the particle size of the methylol amideshall be suitably small. The dispersion obtained by this processcontains the methylol amide in the form of long slender needle-likecrystals which range from about 1 x microns to 2 x 10 microns.

The dispersion is dewatered by filtration or by any equivalent operationand the filter cake is then washed with water to remove any remainingexcess formaldehyde. The filter cake ordinarily contains about tosolids. The speed of filtration is improved markedly by adding a smallamount of calcium acetate to the dispersion near the end of the heatingstep.

The filter cake is then mixed with polyvinyl alcohol and with asurface-active agent consisting of a Water-soluble long-chain alcoholsulfate containing from 12 to 18 carbon atoms. There is added from 10 to30% polyvinyl alcohol, based on the dry weight of methylol fatty acidamides in the filter cake, the preferred amount being from 10 to 20%.The polyvinyl alcohol can be in the form of a commercial partiallysaponified polyvinyl ester. Polyvinyl acetate which is from 80 to 95%saponiiled is particularly suitable. The polyvinyl alcohol is added inthe, form of an aqueous solution.

There is added from 2 to 5% and preferably from 4 to 5% of the longchain alcohol sulfate, based on the dry weight of methylol fatty acidamides. Higher amounts of the surface-active agent seriously interferewith the water-repellent properties of the final product. Anycommercially available water-soluble long-chain alcohol sulfate, such asthe sodium or triethanoL amine salts of the sulfates of the long-chainalcohols obtained by reduction of coconut oil, sperm oil and the like,may be used.

The filter cake containing the methylol amides is mixed with thepolyvinyl alcohol and the longchain alcohol sulfate in any efficientmixer or colloid mill. The resulting mixture is useful directly as atextile finishing composition, producing water-repellent effects whenapplied to and heated on the fabrics. The effects are not as durable aswhen resins are also present, nor does the mixture of methylol amide andpolyvinyl aloohol produce any significant degree of dimensionalstability. These mixtures are stable dispersions which may be stored ortransported without adverse eifect, and which may subsequently be mixedwith resins to form the preferred compositions of this invention.

The water-soluble heat-setting amide-formaldehyde resins which areuseful in the practice of this invention include urea-formaldehyderesins, melamine-formaldehyde resins and 1,3- bis (hydroxymethyl) 2imidazolidone resins. They are most conveniently incorporated with thedispersion of methylol amide and polyvinyl alcohol by adding the resinsin aqueous solution, followed by intimate mixing. The amount of resin tobe added depends upon the nature of the fabric and of the resin and onthe degree of stiffness and dimensional stability which is desired.About 1 part of resin per part of methylol amide represents the minimumamount. In treating viscose rayon, best results are obtained withcompositions containing at least 4.5 parts of urea-formaldehyde resin,about 3.5 parts of melamine-formaldehyde resin or about l parts of1,3-bis- (hydroxymethyl) -2-imidazolidone resin per part of methylolamide. With cotton, excellent results are obtained from compositionscontaining only 1 to 1 /2 parts of resin. Amounts of resin up to about15 parts per part of methylol amide can be used, but at this point thecompositions become undesirably expensive and water repellency begins todecrease.

The preparation of the compositions of this invention is illustrated bythe following examples:

Example 1 A mixture of 202 parts of technical grade stearamide and 808parts of water is heated to 96 C. and agitated at 96-98 C. for five toten minutes to convert it to a smooth, homogeneous paste. The charge isthen cooled to 65 C. and 291 parts of a 37% formaldehyde solution arerun in slowly over one to two hours at 60-65 C. with vigorous agitation.During this addition the charge is kept slightly alkaline tophenolphthalein paper (pl-I 8.5-9.0) by the addition of 30% sodiumhydroxide solution. This pH is maintained while the charge is agitatedvigorously for an additional hour at Bil-65 C.

The mixture is then heated gradually to C. during one hour and agitatedat iii-82 C. for three more hours at the same pH. To aid in n1- trationof the methylol stearamide, 14 parts of calcium acetate are added,followed by an additional hours agitation at 80 C. The charge is cooledto 50-60 C. with agitation and filtered. The filter cake is washed withwater until substantially free of formaldehyde, and pressed until it hasa methylol amide content of about 40%.

The filter cake amounting to about 550 parts is charged into a kettlecontaining 440 parts of a 10% aqueous solution of polyvinyl alcohol(86-89% saponified polyvinyl acetate) 10 parts of the sodium sulfate ofa mixture of long chain alcohols containing from 10 to 16 carbon atoms,predominantly lauryl and myristyl alcohols, and -10 parts of water. Thecharge is agitated at 40-50 C. to a smooth, homogeneous paste and passedthrough a colloid mill to complete the mixing.

The 1000 parts of dispersion resulting from this procedure are mixedwith 1500 parts of a commercially available urea-formaldehyde textileresin in the form of a 20% aqueous solution. Viscose-acetate rayongabardine treated with this mixture possesses good water-repellency,creaseresistance and dimensional stability, and has a firm, crisp hand.

When 1000 parts of 1,3-bis-(hydroxymethyD- 2-imidazolidone are used inplace of the ureaformaldehyde resin, similar effects are obtained,except that the treated fabric is not as stiff.

Similarly, 850 parts of a commercial methylated methylol melamine aremixed with 1000 parts of the methylol amide-polyvinyl alcohol dispersiondescribed above. When the resulting dispersion is applied to rayon, itimparts to the fabric a high degree of water-repellency together withsatisfactory dimensional stability and a firm hand.

Example 2 The general procedure of Example 1 is repeated using lessformaldehyde and different temperatures.

A mixture of 808 parts of water, 202 parts of technical grade stearamideand 81 parts of a 37% aqueous formaldehyde solution is heated to 96 C.and agitated for five to ten minutes at 96-98 C. to convert it to asmooth, homogeneous paste. The charge is cooled to 80 C. in half tothree-quarters of an hour with agitation. The pH is adjusted to about7.5 by the addition of 30% sodium hydroxide solution and the charge isagitated vigorously for two hours at 79-83 0., maintaining the same pH.During this period the charge changes from a light brown, nonhomogeneousmass to a smooth, homogeneous white paste.

After the charge is cooled to 70 C., 14 parts of calcium acetate aremixed in by agitating for about thirty minutes. The charge is furthercooled to 60 C. and filtered. The filter cake is washed free offormaldehyde with water and pressed to 550 parts, having a 40% solidscontent. This produces a methylol amide mixture havin a melting range ofabout 108-110 C.

The filter cake is mixed with polyvinyl alcohol and sodium alcoholsulfate as described in Example 1. When portions of the resultingdispersion are mixed with the urea, melamine and 1,3-.bis-(hydroxymethyl)-2-imidazo1idone resins as in Example 1 and appliedto a rayon fabric, the treated fabrics possess good water-repellency,dimensional stability and firm hand.

The compositions of this invention are prepared for application to thefabric simply by mixing them into water with a small amount of anyconventional mildly or potentially acidic catalyst for curing the resin.Examples of suitable catalysts include tartaric acid, the ammonium acidphosphates, zinc nitrate and the like.

The aqueous dispersion is then applied to the fabric by padding or byany other convenient method. The fabric is dried and baked for about 3minutes at 325 to 375 F. to cure the resin. The treated fabric displaysgood water-repellency and dimensional stability. The hand of the fabricis improved by becoming firmer and more resilient. These effects arequite durabl and survive washing and dry-cleaning of the fabric. Theresin content of the composition serves not only to contributecrease-resistance and dimensional stability but also to bind themethylol amide to the fabric so as to give a more durable water-repehlent effect.

An important advantage of these compositions is that they are quitestable without close control of the pH. This is not true of many otherwater-repellent compositions, as for example dispersions of methylolstearamide in soap solution, which are extremely sensitive to changes inpH.

I claim:

1. A process of preparing a textile finishing composition whichcomprises: (1) forming a dispersion of methylol fatty acid amides byheating together at 60 to 100 C. under vigorous agitation (a) a fattyacid amide mixture which melts between and C. in water and in which thetotal content of stearamide and palmitamide exceeds 80% by weight, (5)water, and (c) a molecular excess of formaldehyde, during a portion ofwhich heating step at least the fatty acid amides and water are agitatedtogether at a temperature bet-ween the melting point of the amidemixture and 100 vC. to emulsify the amides, and during a subsequentportion of which the dispersed fatty acid amide, formaldehyde and waterare agitated at pH 7.5 to 9 and at 75 to 100 C.; (2) filtering off themethylol fatty acid amide and washing out the excess formaldehyde fromthe filter cake; and (3) mixing the filter cake with from 10 to 30%polyvinyl alcohol in aqueous solution and with from 2 to 5% of awatersoluble long-chain alcohol sulfate containing from 12 to 18 carbonatoms, the percentages in each case being based on the dry weight ofmethylol fatty acid amide in the filter cake.

2. A textile finishing composition prepared by the process of claim 1.

3. A textile finishing agent consisting of a composition prepared by theprocess of claim 1 in admixture with from 1 to 15 parts by weight of awater-soluble heat-setting amide-formaldehyde resin per part of methylolfatty acid amide.

4. A composition according to claim 3 in which the resin is aurea-formaldehyde resin.

5. A composition according to claim 3 in which the resin is a,methylated methylol melamine resin.

6. A composition according to claim 3 in which the resin is a1,3-bis(hydroxymethyl)-2-imidazolidone.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,357,273 Thurston Aug. 29, 1944 2,365,813 Gluesenkamp Dec.26, 1944 2,423,428 Pollard July 1, 1947 2,537,667 Harris Jan. 9, 1951FOREIGN PATENTS Number Country Date 495,714 Great Britain Nov. 14, 1939

1. A PROCESS OF PREPARING A TEXTILE FINISHING COMPOSITION WHICHCOMPRISES: (1) FORMING A DISPERSION OF METHYLOL FATTY ACID AMIDES BYHEATING TOGETHER AT 60 TO 100* C. UNDER VIGOROUS AGITATION (A) A FATTYACID AMIDE MIXTURE WHICH MELTS BETWEEN 90 AND 100* C. IN WATER AND INWHICH THE TOTAL CONTENT OF STEARAMIDE AND PALMITAMIDE EXCEEDS 80% BYWEIGHT, (B) WATER, AND (C) A MOLECULAR EXCESS OF FORMALDEHYDE, DURING APORTION OF WHICH HEATING STEP AT LEAST THE FATTY ACID AMIDES AND WATERARE AGITATED TOGETHER AT A TEMPERATURE BETWEEN THE MELTING POINT OF THEAMIDE MIXTURE AND 100* C. TO EMULSIFY THE AMIDES, AND DURING ASUBSEQUENT PORTION OF WHICH THE DISPERSED FATTY ACID AMIDE, FORMALDEHYDEAND WATER ARE AGITATED AT PH 7.5 TO 9 AND AT 75 TO 100* C.; (2)FILTERING OFF THE METHYLOL FATTY ACID AMIDE AND WASHING OUT THE EXCESSFORMALDEHYDE FROM THE FILTER CAKE; AND (3) MIXING THE FILTER CAKE WITHFROM 10 TO 30% POLYVINYL ALCOHOL IN AQUEOUS SOLUTION AND WITH FROM 2 TO5% OF A WATERSOLUBLE LONG-CHAIN ALCOHOL SULFATE CONTAINING FROM 12 TO 18CARBON ATOMS, THE PERCENTAGES IN EACH CASE BEING BASED ON THE DRY WEIGHTOF METHYLOL FATTY ACID AMIDE IN THE FILTER CAKE.